This is a pilot and feasibility proposal to develop femtosecond-pulse two-dimensional infrared correlation spectroscopy (IR-COSY) as a tool for structure determination in the amyloid beta proteins that form parallel beta sheet fibrils, and are difficult to study by the traditional methods of structural biology. The approach will also be applied to study the evolution of such structure during fibrillogenesis. [unreadable] [unreadable] Alzheimer's disease and several others are now recognized to involve the misfolding and aggregation of proteins as parallel beta sheets. A better understanding of this pathological protein structure is key to understanding why these proteins misfold in the first place, and to developing therapeutic interventions for these diseases. [unreadable] [unreadable] [unreadable]